The goal of this project is correlative MR and optical histology of a model of brain damage induced by AET. Recent results have demonstrated neuronal damage detected by MRM in brain specimens from animals treated with DOM. Some of the lesions seen in the MRM specimens were not evident in conventional optical sections with H&E and Nissl stain. If these results can be demonstrated in other models of disease, the implications are enormous. Simply put, this suggests that MRM can detect lesions not seen in conventional histology. This is consistent with other recent evidence in the Center. A total of 9 specimens will be scanned. These are 1/2 the brains of rats that have been treated with AET. The other half brains have already been sectioned and analyzed with conventional histology. Six of these specimens show significant damage in four different nuclei: Superior Olive, trapezial nucleus, red nucleus, facial nucleus. Damage ranges from 10% of the nucleus to as much as 97% of the nucleus. We will scan the second 1/2 brain with 2 protocols: I FSE -TR=1.5sec; TE=50 ms; Nechos=8; fovz=fovy=10 mm; fovx=20 mm; matrix (z,y,x)=256x256x128; nex=2 (Total time 6.8 hrs) II GRASS TR=100 ms.TE=3 ms, alpha=350 , same fov matrix as I, nex=4 (total time =3.64 hrs) We will section the specimens after MR and compare specific regions of interest with quantitative morphometry to describe % cell damage.